Explosive container



April 9, 1968 5 F, FOSTER ET AL 3,376,816

EXPLOSIVE CONTAINER Filed Sept. 6,' 1966 F IG. 3 STEPHEN E FOSTER HOM ER G. MOORE INVENTORS United States Patent C 3,376,816 EXPLOSVE CONTAINER Stephen F. Foster, Hopatcong, and Homer G. Moore, Mine Hill, NJ., assignors to Hercules Incorporated, Wilmington, Del., a corporation of Delaware Filed Sept. 6, 1966, Ser. No. 577,211 4 Claims. (Cl. 102--24) The present invention relates 'to an explosive container of 'the type that forms the subject matter of the U.S. Patent of Hamilton, No. 3,125,092, that is, a |blow-molded plastic container that is filled with explosive and is provided w'ith a coupling means for connecting a plurality of like containers together endtoend to form an explosive column assembly that is adapted to be dropped in a bore hole. More particularly, the present invention relates to the coupling means for connecting such containers to'- gether, and in this respect, constitutes lan improvement in the coupling lme'an's that forms the subject matter of my co-pending application, Ser. No. 577,448, iile'd simultane'ously herewith.

The objects of the present invention are to provide a coupling means for connecting together endwise a plurality of containers for explosives, which coupling means is adapted for quick assembly and for threaded engagement to provide for tightening the joint between containers, as well as for disconnecting the containers if desired, all as disclosed in my above noted copending application, Ser. No. 577,448, and, inaddit'ion, provides a more secure or stronger connection with wall thicknesses equal to that of the design forming the subject matter of my copending application or, conversely, provides an equally strong connection with reduced wall thickness 'and thus more economical design.

In accordance with this invention, the tabs that are formed in the side wall of the female connector at the one end of the container are formed so th'at, when they are deected by the external threads on the male connector 'as the threads pass the same upon endwise assem- 'bly of two containers, a portion of the tab projects outwardly beyond the periphery of the container, and there is provided a sleeve mounted on the periphery of the container for sliding endwise thereo-f into and out of a position over the tabs where it prevents said tabs from projecting outwardly. When deilection of said tabs by the threads is prevented in this manner, relative movement endwise of the containers is also prevented. The sleeve thus constitutes a locking device that reduces the coupling between the containers to a threaded connection. At the same time, the sleeve reinforces the side wall of the container against 'deformation under stress, particularly at the ibase of the tabs which constitutes their hinge line, and thus strengthens the coupling.

A preferred embodiment of the invention is hereinafter disclosed with reference to the accompanying drawings, in which:

FIG. 1 is an elevational view of a container in accordance with this invention, with parts ibroken `away for convenience and for showing the underlying construction.

FIG. 2 is a fragmentary detail view in section of the I connection y,between two of the containers of FIG. 1 joined together end-to-end.

'FIG. 3 is a fragmentary detail View in section of a portion of the connection illustrated in FIG. 2 but with the parts in a ydifferent position in t-he assembly thereof.

With reference to the drawings, the present invention is lillustrated as embodied in a container l1 that is blow molded from a suitable plastic material such as high density polyethylene. The container 1 consists essentially of a relatively thin, elongated, substantially cylindrical side wall that includes a central body portion 2 which V engage the threads 3,3 76,8 l 6 Patented Apr. 9, 1 968 constitutes the major portion of the container, and, at the opposite ends thereof, a threaded end portion 3 and a tubular end portion 4. The container is closed at its opposite ends yby closure means comprising an end wall 5 formed integrally at the end of the threaded end portion 3 and a transverse seal `6 having the peripheral edge thereof seated in a groove 7 internally of the side wall of the container yat the juncture of the body portion 2 and the tubular end portion i4, and particularly at the outwardly projecting reinforcing rib 8. The closed portion of the container 1, that is, the body portion 2 land the threaded end portion 3, is -iilled with an explosive 9.

For connecting a plurality of the containers 1 together end-to-end to form an explosive column assembly, there is provided a coupling means comprising an external screw thread 10 formed integrally on the periphery of the threaded end portion 3, which is the male coupling element, and a series of tabs 11 formed in the side wall of the tubular end portion 4, which is the female coupling element.

The tabs 11 are formed integrally in the side Wall of the tubular end portion 4, as during the blow molding operation in which the container is formed, and comprises short, individual lengths of a discontinuous internal screw threlad -spiraily of the portion 4 and having a pitch and being otherwise dimensioned to cooperate with the thread '10 on the threaded end portion 3. After the blow molding operation, the tabs 11 are severed from the side wall of the tubular end portion 4 along that edge which, with the container oriented as illustrated tin FIG. l, is the lower edge and along both of the side edges. Thus, each tab l11 is connected to the side wall of the tubular end portion 4 only along a line 12 at the upper edge thereof and which, because of the inherent resilience of the material, constitutes a hinge line for the tab. When the tabs 11 are ysevered from the side wall of lthe container on all sides except along the hinge lines 12, there are produced apertures 13 in the side wall, which apertures are normally substantially closed by the tabs ylll.

Formed as above described, each of the tabs 11 is generally cup-shaped in cross section or, in other words, is concave inwardly from the periphery of the side wall of the tubular end portion 4 of the container. The tabs 1'1 are preferably given a slight set inwardly of the apertures 13, as by using a heated punch, so that they normally stand inwardly slightly, as illustrated in FIG. 2, and normally extend into the grooves 14 between the threads 10.

The upper surface 15 of each of the tabs 11 is inclined downwardly and inwardly relatively to the axis of the container to provide a cam sur-face which is adapted to '10 when the threaded end portion 3 of one container is inserted endwise int'o the tubular end portion 4 of another container. The t'abs 11 are thus `adapted to ybe deflected outwardly about their hinge line's '12 to the deflected position illustrated in FIG. 3 by the threads 10 upon relative movement endwise between the threads and the tabs. As each turn of the thread 10 passes a tab, the tab recovers from its deflected position into the groove 14 between the threa'ds.

The lower surface 16 of each of the tabs 11 is rela- Vtively flat, that is, nearly normal to the axis of the container, and constitutes the active surface of the tab, which is the surface that cooperates with the thread 10 when two joined containers are rotated relatively so that the threaded connection aiforded by the tabs 11 and thread 10l draws the same together. The lower or active surfaces 16 of the successive tabs 11 are arranged spirally about the side wall of the tubular end portion on a helix angle corresponding to that of the thread 10 so that all of the tabs 11 will cooperate simultaneously with the thread 10.

When engaged and deflected by a thread 10, each of the tabs 11 moves outwardly through the respective aperture 13 to the deflected position as illustrated in FIG. 3. In this position, a substantial portion of the tab, and particularly that -portion adjacent to the lower or free edge 17 thereof, is disposed outwardly of the periphery of the side wall of the tubular end portion 4 of the container. In order to lock the tabs against deflection to the deected position, there is provided a sleeve 18 that is slidably mounted on and closely embraces the periphery of the tubular end portion 4 of the container and is adapted to rest normally upon the shoulder 19 provided by the upper edge of the circumferential reinforcing rib 8. In this position, the sleeve 18 overlies each of the apertures 13 and is engaged by the free edge 17 of the tabs 11 when the tabs 11 tend to move to the deflected position, thereby preventing deection of the tab and at the same time preventing endwise movement of the threads 10 relative to the tabs 11. In this manner, the sleeve 18 becomes a locking device and the free edges 17 of the tabs 11 become a locking surfaces and, when the sleeve 18 is in its operative position as illustrated in FIG. 2, the tabs 11 are prevented from moving to the deflected position. In this manner, the relative movement between two joined containers is confined to the threaded connection afforded by the thread 10 and the tabs 11.

Y In the assembly of a plurality of the containers 1 into an explosive column assembly, the sleeve 18 of the one container is moved away from the shoulder 19 a distance suicient to clear all of the apertures 13. The threaded end portion 3 of another container can then be inserted endwise into the tubular end portion of the first container, with the tabs 11 of the first container alternately being deflected by the individual turns of the thread 10 and recovering to move into the groove 14 between Successive turns of the thread 10. When the threaded end portion 3 has been inserted as far as it will go with the tabs in their normal position in the groove 14, the sleeve 1 8 is moved onto the shoulder 19 and a relative rotation is imparted to the containers. Through the threaded connection afforded by the tabs 11 and the thread 10, the two containers can be drawn tightly together to force the end wall 5 of the one container against the seal 6 of the other container to provide intimate contact between the explosives 9 in each container and thus to insure propagation of the explosion. The amount of turning required would be course depend upon the angular orientation of the tabs 11 with the thread 10 at the time they were mated, but there would normally be required no more than a single turn for a single lead thread 10 and one-half a turn for a double lead thread. In the event that, after assembly, it was decided for any reason to uncouple one container from another, this can be effected by virtue of the threaded coupling afforded by the tabs 11 and thread 10.

When the sleeve 18 overlies the apertures 13, not only, are the tabs 11 prevented from moving to the deected position, but also, the sleeve acts to reinforce the tubular end portion of the container against bending in the area of the joint, and also supports the side wall of the tubular end portion 4 against bulging outwardly at the base of the tabs 11, that is, at the hinge line 12. From the standpoint of added strength, the end walls 20 of the tabs 11 also add significant support to the tabs between the active surface 16 and the hinge line 12 to prevent buckling of the tab, so that the stress is transferred more efficiently to the side wall of the tubular end portion 4 of the container at a point where the side wall is prevented from bulging outwardly by the sleeve 18,

What we claim and desire to protect by Letters Patent is:

1. In a blow-molded plastic container adapted to be filled with an explosive and to be connected into an explosive column assembly with like containers, a substantially cylindrically side wall including a central body portion with a threaded end portion and a tubular end lportion at the opposite ends thereof, closure means for closing said container at the end of said threaded end portion and at the juncture of said tubular end portion and said body portion, said threaded end portion having an integral external screw thread dimensioned relative to said tubular end portion whereby the threaded end portion of the container is adapted to be inserted endwise into the tubular end portion of a like container, said tubular end portion having a plurality of tabs formed in the side wall thereof with each of said tabs being resilient and adapted to be deflected by said thread, said tabs having an active surface spirally of said tubular end portion on a helix angle corresponding to that of said thread and adapted to cooperate with the thread of a like container to provide a threaded coupling therewith; the improvement comprising a sleeve slidably mounted on and closely embracing the periphery of said tubular end portion said sleeve being movable endwise of said container to a locking position overlying said tabs and a released position clear of said tabs, said tabs having locking surfaces adapted to engage against said sleeve in the locking position to prevent movement of said tabs to the deflected position and thereby preventing movement of said thread relative to said tabs endwise of the container while providing a threaded connection between a pair of joined containers.

Z. In a blow-molded plastic container in accordance with claim 1 in which the side wall of said tubular end portion of the container is provided with an aperture adjacent to each tab, said tabs 'being integral with said side wall along hinge lines disposed at the edges of said aperture, and being adapted to move through said aperture to the deected position and into contact with said sleeve.

3. In a blow-molded plastic container in accordance with claim 2 in which said tabs are concave inwardly of the container and are integrally connected to said side wall along a hinge line, said active surfaces of said tabs being disposed along the free edges of said tabs, and said tabs include side walls extending from said free edge to said hinge line.

4. In a blow-molded plastic container in accordance with claim 1 in which said tabs comprise sections of a discontinuous internal screw thread formed integrally in the side wall of said tubular end portion of the container, said tabs being severed Ifrom said side wall along the active surface thereof and being connected to said side wall along a 4hinge line opposed to said active surface, said side wall having an aperture from which said tab was severed and through which the locking surface of said tab moves to be deflected position and into contact with said sleeve.

References Cited UNITED STATES PATENTS 2,398,553 4/1946 Nyden 215-43 2,865,290 12/1958 Bonsper 102-24 X 3,186,340 6/1965 Foster 102-24 3,306,200 2/ 1967 Branscum 220-39 X THERON E. CONDON, Primary Examiner.

G. E. LOWRANCE, Assistant Examiner. 

1. IN A BLOW-MOLDED PLASTIC CONTAINER ADAPTED TO BE FILLED WITH AN EXPLOSIVE AND TO BE CONNECTED INTO AN EXPLOSIVE COLUMN ASSEMBLY WITH LIKE CONTAINERS, A SUBSTANTIALLY CYLINDRICALLY SIDE WALL INCLUDING A CENTRAL BODY PORTION WITH A THREADED END PORTION AND A TUBULAR END PORTION AT THE OPPOSITE ENDS THEREOF, CLOSURE MEANS FOR CLOSING SAID CONTAINER AT THE END OF SAID THREADED END PORTION AND AT THE JUNCTURE OF SAID TUBULAR END PORTION AND SAID BODY PORTION, SAID THREADED END PORTION HAVING AN INTEGRAL EXTERNAL SCREW THREAD DIMENSIONED RELATIVE TO SAID TUBULAR END PORTION WHEREBY THE THREADED END PORTION OF THE CONTAINER IS ADAPTED TO BE INSERTED ENDWISE INTO THE TUBULAR END PORTION OF A LIKE CONTAINER, SAID TUBULAR END PORTION HAVING A PLURALITY OF TABS FORMED IN THE SIDE WALL THEREOF WITH EACH OF SAID TABS BEING RESILIENT AND ADAPTED TO BE DEFLECTED BY SAID THREAD, SAID TABS HAVING AN ACTIVE SURFACE SPIRALLY OF SAID TUBULAR END PORTION ON A HELIX ANGLE CORRESPONDING TO THAT OF SAID THREAD AND ADAPTED TO COOPERATE WITH THE THREAD OF A LIKE CONTAINER TO PROVIDE A THREADED COUPLING THEREWITH; THE IMPROVEMENT COMPRISING A SLEEVE SLIDABLY MOUNTED ON AND CLOSELY EMBRACING THE PERIPHERY OF SAID TUBULAR END PORTION SAID SLEEVE BEING MOVABLE ENDWISE OF SAID CONTAINER TO A LOCKING POSITION OVERLYING SAID TABS AND A RELEASED POSITION CLEAR OF SAID TABS, SAID TABS HAVING LOCKING SURFACES ADAPTED TO ENGAGE AGAINST SAID SLEEVE IN THE LOCKING POSITION TO PREVENT MOVEMENT OF SAID TABS TO THE DEFLECTED POSITION AND THEREBY PREVENTING MOVEMENT OF SAID THREAD RELATIVE TO SAID TABS ENDWISE OF THE CONTAINER WHILE PROVIDING A THREADED CONNECTION BETWEEN A PAIR OF JOINED CONTAINERS. 